Ahhhh, the memories.

Back about 1990 I had the Alternator Bolt snap while driving home, with 150 miles and a ferry ride between me and my driveway.

So ..... no radio, and we had to drive sportly to get home before it got dark, we even Bump started it to get it off the Ferry and save a few Joules.

The car made it, about 3 hrs of driving just on the battery and a couple of amps generated by the slack belt, which also caused drastically reduced flow of the water pump.

So, if you have a 90º drill you can drill out the remaining bolt, and then get a new Grade 8 bolt and put a bit of Anti Sieze grease on it, and DON't over torque the new bolt. The Alternator is held in place primarily by the top adjustment bolt and the lower bolt should not be Over Torqued to keep position (= the tension)

Not sure what the torque spec is for these bolts but easily found, and most likely also in the Greenbook.

 

Ahhhh, the memories.

we even Bump started it to get it off the Ferry and save a few Joules.

'Bump started' - a term generally not in the lexicon of vehicle owners born after 1980.

For those of us who grew up with cars equipped with Lucas Prince of Darkness electrics, bump starting was a required skill.

 

Matheu;

Such a failure is a rare occurrence, but not one which hasn't happened before...and galling apparent on the pivot from 1-4 O'Clock is clear evidence that pivot bolt or Fanbelt tensioning bar, or both were loose, allowing movement of the Alt, causing cyclic forces on bolt which caused breakage...there is certainly plenty of vibration input from the belt! Alternator should be checked to be absolutely secured to block and not being able to move in any axis...good practice is to check for secureness or Alt (and tightness of Fanbelt) any time hood is opened for fluid checking or other service.

On the Alt conversion brackets which I offer, the ONLY failures which have occurred on Alt housing, or bracket or pivot bolt, have occurred for the same reason: Looseness, and the fact that there was relative movement between Alt case and bracket, or bracket and block! If Pivot bolt is properly torqued, after the Fanbelt has been tensioned, Alt will be securely ONE with block, and will stay that way!...but I include a nylock jamnut in my kit for additionally locking the pivot bolt in place (belt and suspenders...a triple safety feature, just because I can!).

Cheers

 

Matheu;

Such a failure is a rare occurrence, but not one which hasn't happened before...and galling apparent on the pivot from 1-4 O'Clock is clear evidence that pivot bolt or Fanbelt tensioning bar, or both were loose, allowing movement of the Alt, causing cyclic forces on bolt which caused breakage...there is certainly plenty of vibration input from the belt! Alternator should be checked to be absolutely secured to block and not being able to move in any axis...good practice is to check for secureness or Alt (and tightness of Fanbelt) any time hood is opened for fluid checking or other service.

On the Alt conversion brackets which I offer, the ONLY failures which have occurred on Alt housing, or bracket or pivot bolt, have occurred for the same reason: Looseness, and the fact that there was relative movement between Alt case and bracket, or bracket and block! If Pivot bolt is properly torqued, after the Fanbelt has been tensioned, Alt will be securely ONE with block, and will stay that way!...but I include a nylock jamnut in my kit for additionally locking the pivot bolt in place (belt and suspenders...a triple safety feature, just because I can!).

Cheers

Oh cool Ron, awesome you joined the thread. What I think occurred in this case was the prior owner had a belt that was way too long installed (And I had not remedied that yet) so the alternator is adjusted all the way to the end. Since this car diesels on shutdown every so often, the severe shaking that occurs had slammed the alternator itself against the bolts for the idler arm mount. This eventually stressed the lower bolt so badly it broke since it itself probably wasn't tight as you deduced by the wear patterns on the cast mounting ear. Dunno how long this had been going on prior to me buying he car earlier this year (this car was resurrected from resting under a tree in 2012). The alternator casing itself has impact scars from this happening. I'm looking forward to getting the mount from you, it sounds like it's well made from your description. It is probably better made than the one I stick welded together in 1988 for my first 140 Volvo. My remanufactured 10si arrived on Monday so I'm partway to getting this done.

Any idea what length 5/16" NC bolts I should get to attach it to the block?

 

Mathue;

There plenty of questions for the (even) older cars, so I only occasionally check into the 140 forums...

I can't agree that length of Fanbelt has any bearing on this IF adjusted properly AND Alt is properly tightened after that, because lower pivot and upper Belt tightening bar secure the Alt housing completely. That unmistakable galling can only be a result of continuous vibration and movement, and there must be NONE! Impact scarring is different in that it occurs after the mounting failure, when Alt housing bangs into things because it is free to move in totally unusual ways and places...

SW-EM bracket is highly accurately laser cut and pro welded. It should be secured to block with three 5/16"-18UNC X 3/4" -1" bolts, and Alt must be secured to bracket. Variations and special conditions which have been known to occur are all specifically covered in the installation instructions, but the bottom line is Alt must essentially be ONE with block...NO movement is allowed between Alt and bracket or bracket and block!

Cheers

 

Oh, it's quite possible it had not been tightened properly before I purchased the car. When I do the conversion I take a shot or two of the impact dimples where the body of the stock alternator hit the stud for the steering idler arm.

I'll grab some bolts this week!

 

Woo!

I got the SW-EM alternator kit!

On the back side of the bracket you can see the unpainted spot for the ground (I cleaned and brightened the cast iron on the block before attaching).

Note the rectangular shape to the right of the clean pad. This is a mortise and tenon. In addition to all the welds and the threaded insert this is a VERY stout bracket.

Installation is straight forward. The three bolt holes were chased. The forward most bolt needs to be sent in using a wrench due to clearance with the bracket, the two rearward ones can be sent in with a ratchet.

Once I'd clocked my 10SI alternator properly, bolting it in was easy. Electrical was simple enough to get things charging, I still need to sort and tidy things.

I will be checking the installation regularly over the next few weeks to make sure things stay tight, though with the lock washers I'm not too concerned. I need to more precisely bend the top adjustment strap.

 

Mathue;

I'm glad the installation worked out for you, and got you back charging...just make sure Alt is solidly part of engine block...and stays that way!...correct on the mortise and tenon joint...it's one of the most positive and strongest ones possible, where mortise, and not only weld-joint are subjected to forces (not to say that joint couldn't be broken by vibrating, as occurred here):

I would like to see your pics...maybe it's me, or my settings, but I can't see attachments.

and thanks for unsolicited feedback and review.

Cheers

Edit: Now I can see pix...tnx!

 

I edited my post, hopefully the images are viewable.